linux/net/tipc/node_subscr.c
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   1/*
   2 * net/tipc/node_subscr.c: TIPC "node down" subscription handling
   3 *
   4 * Copyright (c) 1995-2006, Ericsson AB
   5 * Copyright (c) 2005, 2010-2011, Wind River Systems
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions are met:
  10 *
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 3. Neither the names of the copyright holders nor the names of its
  17 *    contributors may be used to endorse or promote products derived from
  18 *    this software without specific prior written permission.
  19 *
  20 * Alternatively, this software may be distributed under the terms of the
  21 * GNU General Public License ("GPL") version 2 as published by the Free
  22 * Software Foundation.
  23 *
  24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34 * POSSIBILITY OF SUCH DAMAGE.
  35 */
  36
  37#include "core.h"
  38#include "node_subscr.h"
  39#include "node.h"
  40
  41/**
  42 * tipc_nodesub_subscribe - create "node down" subscription for specified node
  43 */
  44
  45void tipc_nodesub_subscribe(struct tipc_node_subscr *node_sub, u32 addr,
  46                       void *usr_handle, net_ev_handler handle_down)
  47{
  48        if (addr == tipc_own_addr) {
  49                node_sub->node = NULL;
  50                return;
  51        }
  52
  53        node_sub->node = tipc_node_find(addr);
  54        if (!node_sub->node) {
  55                warn("Node subscription rejected, unknown node 0x%x\n", addr);
  56                return;
  57        }
  58        node_sub->handle_node_down = handle_down;
  59        node_sub->usr_handle = usr_handle;
  60
  61        tipc_node_lock(node_sub->node);
  62        list_add_tail(&node_sub->nodesub_list, &node_sub->node->nsub);
  63        tipc_node_unlock(node_sub->node);
  64}
  65
  66/**
  67 * tipc_nodesub_unsubscribe - cancel "node down" subscription (if any)
  68 */
  69
  70void tipc_nodesub_unsubscribe(struct tipc_node_subscr *node_sub)
  71{
  72        if (!node_sub->node)
  73                return;
  74
  75        tipc_node_lock(node_sub->node);
  76        list_del_init(&node_sub->nodesub_list);
  77        tipc_node_unlock(node_sub->node);
  78}
  79
  80/**
  81 * tipc_nodesub_notify - notify subscribers that a node is unreachable
  82 *
  83 * Note: node is locked by caller
  84 */
  85
  86void tipc_nodesub_notify(struct tipc_node *node)
  87{
  88        struct tipc_node_subscr *ns;
  89
  90        list_for_each_entry(ns, &node->nsub, nodesub_list) {
  91                if (ns->handle_node_down) {
  92                        tipc_k_signal((Handler)ns->handle_node_down,
  93                                      (unsigned long)ns->usr_handle);
  94                        ns->handle_node_down = NULL;
  95                }
  96        }
  97}
  98